System for controlling the stability of a vehicle using several predictive algorithms and a selection process

Abstract

System for controlling the stability of a vehicle, the system comprising means for imparting a longitudinal force to the tire and means for calculating a slip GOpt by determining the values of the coefficient of friction μi, for each slip Gi corresponding to successive levels “i”, using in parallel “n” calculation algorithms each determining a target value of the slip making it possible thus to obtain as many target values GCn as there are algorithms used, the system selecting the best of the target values GCn as the optimum slip value GOpt by subjecting the “n” target values GCn to comparisons aimed at eliminating the least likely target values, the comparisons being made on the basis of a function f(λ) of a descriptor of the physical functioning of the rotation of the tire on the ground making it possible to calculate characteristic values. For example, one interesting characteristic value is the variation in G with respect to time.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit of French Patent Application No. 04 / 00422, filed Jan. 16, 2004, and French Patent Application No. 04 / 05823, filed May 27, 2004, both of which are incorporated herein by reference in their entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to vehicle stability control systems. In a particular application, the invention relates to systems aimed at preventing the locking of the wheels during hard braking, popularized by the term “ABS”. More generally, the invention concerns all systems aimed at maintaining the vehicle on a stable path by acting automatically on actuators such as those determining a wheel driving or braking torque, or those determining the steering of one or more wheels, or even those concerning the suspension, where it is known that this also has an effect on the control of the path (for example active antiroll). In the particular application...

AI Technical Summary

Benefits of technology

[0020]The present invention therefore proposes, according to observations made at the very start of each torque variation maneuver (typically at the very start of each braking maneuver but this is valid also at the start of each acceleration or for other maneuvers such as turning), from observations (measurements or estimations), to calculate the target slip values according to several algorithms and to select from amongst these targets the optimum slip value finally adopted by the regulation of the slip. The result aimed at is therefore to maintain the value of the coefficient of friction of the tire at a value chosen as being ideal in the situation of the vehicle of the moment, for example at its maximum possible value.

Problems solved by technology

However, the average driver is not capable of tuning out the braking so as to satisfy this condition.

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